This invention relates to electroluminescent devices and more particularly to electroluminescent devices whose radiating light is columnated, i.e. forms a parallel beam.
In the field of electroluminescent devices, i.e., light emitting diodes and lasers, the light emanating from the emitting surface has a divergent quality. Divergent light is light whose beam spreads as it travels from its source. Divergence of emitted light is troublesome when it is desirable to couple an electroluminescent device to an external optical system. The divergence of the emitted light makes it difficult to assume that all of the light will be coupled into the external optical system. Therefore, it would be most desirable to have an electroluminescent device whose emitted light beam is substantially collimated for optical coupling.